Pump Installation; Installation; Rotation Direction; Hydraulic Connections - Pratissoli SKH Serie Manual De Uso

9

PUMP INSTALLATION

9.1

Installation

The pump must be fixed horizontally using the Ø19 drilled
support feet.
The base must be perfectly flat and rigid enough as not
to allow bending or misalignment on the pump coupling
axis/transmission due to torque transmitted during operation.
Two lifting eyebolts are mounted on the pump for easy
installation, as per the figure below.
Replace the oil filling hole closing service
plug (red) positioned on the rear casing cover.
Check the correct quantity with the oil dipstick.
The oil dipstick must always be reachable, even
when the unit is assembled.
The pump shaft (PTO) must not be rigidly
connected to the drive unit.
The following types of transmission are
recommended:
- Flexible coupling.
- Universal joint (comply with the maximum
working angles recommended by the
manufacturer).
9.2

Rotation direction

The rotation direction is indicated by an arrow located near
the drive shaft.
From a position facing the pump head, the rotation direction
will be as in Fig. 6.
LH SIDE
anticlockwise
The drive can be taken from either side of the pump.
The pump is generally supplied with the PTO shank on the
right-hand side (see Fig. 6).
To have the drive on the left-hand side you need to remove
Fig. 5/a
the shaft end cover and fit it on the right-hand side of the
pump (see par. 2.1.1 of the Repair manual).
On the contrary, the tab must be removed from the right-hand
side and inserted onto the shank on the left-hand side.
9.3

Hydraulic connections

In order to isolate the system from vibrations produced by
the pump, it is advisable to make the first section of the duct
adjacent to the pump (both suction and outlet) with flexible
piping. The suction hose must be sufficiently rigid to prevent
deformation due to the negative pressure exerted by the
action of the pump.
9.4

Pump supply

SKH pumps require a positive suction head (NPSHr) of
between 5 and 7 bar measured at the head inlet.
The booster supply pump must have at least twice the flow
rate of the plunger pump's rated flow rate with a minimum
pressure of 5 bar.
These supply conditions must be observed at all operating
speeds.
The operation of the booster pump must be independent
from that of the plunger pump.
The booster pump must always be started up
before the plunger pump.
It is advisable to install a pressure switch on the
supply line downstream of the filters protecting
the pump.
9.5

Suction line

For smooth operation of the pump, the suction line must have
the following characteristics:
1. Minimum internal diameter as indicated in the graph in
par. 9.8 and in any case equal to or exceeding that of the
pump head.
Localized restrictions should be avoided along the
suction line as these can cause pressure drops with
resulting cavitation. Avoid 90° elbows, connections
with other piping, restrictions, reverse gradients,
inverted U-curves and Tee connections.
2. The layout must be such as to prevent cavitation
problems.
3. Completely airtight and constructed to ensure a perfectly
hermetic seal through time.
4. Prevent the pump from emptying when it is stopped,
including partial emptying.
5. Do not use 3 or 4-way hydraulic fittings, adapters, swivel
joints, etc. as they could jeopardize pump performance.
6. Do not install Venturi tubes or injectors for detergent
suction.
21
RH SIDE
clockwise
Fig. 6